The amount of water available to a tree determines its susceptibility to drought. It has been one of the big unknowns in predicting responses to climate change. Here we show that it can be measured:

We apply this model to multiple seasonal droughts with tree transpiration measurements to demonstrate how species and size differences modulate moisture availability across landscapes. The depletion of individual moisture reservoirs can be tracked over the course of droughts and linked to biomass growth and reproductive output. This mass balance approach can predict individual moisture deficit, tree demographic performance, and drought vulnerability throughout forest stands based on measurements from a sample of trees, more here https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecy.2499